ok here goes... on the shift indicator all of the shift positions are lit up and when you go to shift into gear it none of the lights will go out or indicate what gear you are in . the car will run and drive but will only go about 20 mph going forward and it will not shift. but it will go like hell in reverse. i hooked a scan tool up to it and got code p1746 now the car had sat for a year and the battery was dead could this have caused this problem? i have another transmission control module and i am thinking about changing it.am i on the right track or am i looking at a much bigger problem than i realize? have any of you guys experienced this problem and how did you fix it? any and all help will be greatly appreciated. Thanks,Tyler

 

It could be the TCU or the relay that supplies power to it. Check the relay first. Then try the other TCU. Sitting for a year shouldn't have caused this but you never know.

 

thanks for the info,next time im out at the farm i will check the relay then if thats good i will put the other tcu in and let you know how i made out. thanks,Tyler

 

ok got to work on the a4 last night checked power to the relay and had power there so i pulled the carpet up to get to the tcu and it was damp under there so i think i have found my problem but i noticed when i was putting it in the garage it wants to shift from first to second but at right about 10 mph you can hear the abs unit applying the brakes and it will hold the car at 10 but if you drop below 10 brakes go off and it will speed up a little. if the tcu is bad will it make the abs unit throw fits and somehow put the car in limp mode? i was also wondering if i could unplug the abs module and see if it still tries to apply the brakes over 10 mph. thanks again,Tyler

 

ABS applying the brakes? My understanding that is ABS can only release pressure on the caliper to prevent lock up. ABS is not an active braking capable system. At least not on the older cars. I suspect the issue is the dampness and things are still not dried out. You'll need to get the car dried out and find out why it's leaking. I suspect that the drains for the firewall tray where the climate control fan is located are stopped up with crud. You'll need to get them unstopped. There's one under the fan box and two on either side that drain out in the wheel well. Those two are easy to get to. The middle one is a bit harder but it can be done with a flexible hose (half inch or smaller) that you can blow some compressed air though to help blow out the crud. Also on the inside there are two drains on either side of the center console under the dash that drain condensation water from the A/C into the center tunnel over the transmission. These are notorious to get stopped up easily and can help aid in flooding the floor if left out in the weather. They are made of silicone rubber are a very soft. They are closed up on the ends to prevent debris from coming back into them from the outside but I ended up having to cut the last little bit off of them because they would not drain completely and the water sitting in them would funk over and grow some lifeform in them that would stop them up again.

This video may help.

 

got the drain funnel out of the ac box and cleaned it and the drains out it actually seemed as if someone was in there recently because they were fairly clean but i did manage to get some crud out of them and i did end up cutting a little bit of the ends off so they hopefully wont plug up again but upon further inspection i found that the water seems to be getting in through the sunroof so it looks like ill be figuring out how to reseal that and hopefully ill be putting that other tcu in the car so i can see what happens so far its been a good learning experience because this is the first audi i have owned,actually its the first car of mine that has not been from the 60's.

 

"cutting a little bit off the ends". That's what I did on mine and i've not have any issues since. The drain for the sunroof could also be plugged somewhere. If you have a Weed-Eater trimmer and you use the flexible plastic line (twine)for the trimmer head, you can use this stuff for slipping into the drain from the top and feeding it though to see if you can knock what ever is stopping it up. Don't get aggressive with it as you might knock the line off where it is connected to the rain tray around the sunroof. Then you'll have to remove the head liner to reattach it. DOH!!! The bottom ends of the drains are usually not as easily accessible but if you can locate them, running a length of twine up into them to see if anything comes out. I'd shoot a little water down into them to see if you can determine whether they are flowing and this also may help locate them under the car.

 

well after putting the other tcu in the car shifts smooth and seems to run pretty good but i think moisture may have gotten to the abs control module because something is causing the rear brakes to apply it happened to me twice on a 15 minute test run and it only seemed to do it at slower speeds but if you kept it moving along it would not do it so i am thinking about picking up another abs control module, if i unplug the abs control module and take it for a ride to see if the brakes still come on will i damage any of the electronics? im thinking the same thing may have happened with this as the tcu because there were signs of moisture under the backseat.

 

I wouldn't think so but the ABS warning light will complain about it. LOL You've got to find out why all that water got in there to start with though. I think the rear sunroof drains would be the culprit there.

 

well it turns out that the abs module was the culprit i unplugged it then took it on a half hour drive with no issues so i brought it back to check into the sunroof drains (which are plugged by the way) so i shut the car off for about 10 minutes then went to start it and it would not restart so hopefully i will be able to get the spark tester on it tomorrow and see if it has any spark ,i am really hoping this is nothing major. so before i go tearing into this do you have any suggestions? thanks again,Tyler